Retaining wall system

ABSTRACT

The present invention concerns embodiments of a block subassembly, a building block system and methods for constructing a retaining wall. In an illustrated embodiment, a block subassembly includes at least a first block and a second block and an adjustable connector which extends between the first and second blocks and is connected to the blocks. The adjustable connector is configured to have an adjustable length to adjust the spacing between the first and second blocks. In particular embodiments, the adjustable connector is pivotably connected to the first and second blocks.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 60/964,311, filed Aug. 10, 2007, which is incorporatedherein by reference.

FIELD

The present invention concerns embodiments of construction blocks,connectors and structures made therefrom, and more particularly toretaining wall blocks and retaining walls for retaining slopes of earth.

BACKGROUND

Conventional retaining walls are used to secure earth embankmentsagainst sliding and slumping. Retaining walls are made of variousmaterials such as concrete, solid masonry, wood ties, bricks and blocksof stone and concrete. Typically, blocks are placed in rows overlayingon top of each other to form a wall. One specific approach for buildinga retaining wall was shown in U.S. Pat. No. 5,350,256 to Hammer. In thisapproach, the retaining wall comprises vertically-stacked courses, eachcomprising a series of I-shaped subassemblies placed side-by-side inrespective courses. Each subassembly is comprised of face and tailblocks that are connected by a trunk block extending between the faceand tail blocks. The chambers defined between adjacent I-shapedsubassemblies are filled in with backfill.

Despite such inventions, there exists a continuing need for new andimproved systems, block subassemblies and methods for constructingretaining walls.

SUMMARY

According to one aspect, the present invention provides a new andimproved adjustable connector for use in block subassemblies that areused to construct retaining walls. According to one embodiment, theadjustable connector is configured to interconnect first and secondspaced-apart blocks and has an adjustable length to adjust the spacingbetween the blocks to form block assemblies of different depths.According to another embodiment, the connector is pivotably connected toone or both of the first and second blocks to permit pivoting of theconnector in a horizontal plane relative to one or both of the blocks.

According to one representative embodiment, a block subassemblycomprises a first block, a second block and an adjustable connectorwhich extends between and is connected to the first and second blocks.The second block is spaced from the first block such that the blocksdefine a space between them to receive backfill material whenconstructing the wall. The length of the adjustable connector can beadjusted to adjust the spacing between the first and second blocks.Typically, in prior art systems such as described above, multiple blocksubassemblies are placed end-to-end in the lower courses of a retainingwall. Advantageously, utilizing a block subassembly with an adjustablelength connector can reduce the number of required subassemblies at thebase of a wall, thereby reducing the amount of materials and timerequired for constructing the wall.

In one illustrated embodiment, the adjustable connector comprises aninner tube nested within an outer tube such that the inner tube istelescopically slidable into and out of the outer tube to adjust thelength of the connector. The inner and outer tubes can have a pluralityof respective longitudinally spaced alignment holes sized to receive aretaining pin. Once the connector is adjusted to its desired length, thepin can be inserted through an alignment hole in each of the inner andouter tubes to restrict relative longitudinal movement between thetubes.

According to another representative embodiment, the present inventionprovides a building block system for building a retaining wall using aplurality of face blocks each having a rear face, a plurality of tailblocks each having a front face and a rear face, and a plurality ofadjustable connectors each having first and second end portions. Thelength of each adjustable connector between its first and second endportions can be adjusted. The face blocks, tail blocks, and adjustableconnectors can be assembled into respective block subassemblies. Eachsubassembly can be formed by connecting the first end portion of anadjustable connector to the rear face of a face block. The adjustableconnector extends rearwardly from the rear face of the face block and isconnected at its second end portion to the front face of a tail block.In certain embodiments, the tails block can be adapted to be connectedto an adjustable connector at its rear face to allow additionaladjustable connectors and tail blocks to be added to the subassembly toextend the subassembly deeper into the slope of the wall for addedanchoring strength.

According to another representative embodiment, a retaining wallcomprises at least first and second vertically stacked courses orlayers. Each course can be constructed by placing several blocksubassemblies side-by-side along the length of each course. Each blocksubassembly includes a face block having a front surface exposed in aface of the wall, a tail block positioned behind and spaced from theface block, and an adjustable connector extending between the two blocksand connected to the face and tail blocks. The length of the adjustableconnector can be adjusted to adjust the spacing between the face andtail blocks.

According to another representative embodiment, a method of constructinga retaining wall is provided. The method includes forming at least firstand second vertically-stacked courses each comprising a plurality ofblock subassemblies. At least some of the block subassemblies include aface block, a tail block and an adjustable connector, the length ofwhich can be adjusted to adjust the spacing between the face and tailblocks.

According to another representative embodiment, a block subassembly forconstructing a retaining wall comprises a first block, a second blockspaced from the first block, and a connector comprising an elongatedbody having first and second opposite end portions. The first endportion is connected to the first block and the second end portion isconnected to the second block, and the connector is pivotable relativeto at least the first block to permit adjustment of the angle betweenthe connector and the first block.

The foregoing and other features and advantages of the invention willbecome more apparent from the following detailed description of severalembodiments, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a retaining wall, according to oneembodiment. FIG. 2 is a top plan view of a block subassembly used toconstruct the wall shown in FIG. 1.

FIG. 3 is a top plan view of the adjustable connector of the subassemblyshown in FIG. 2.

FIG. 4 is a top plan view of the adjustable connector shown in adisassembled state.

FIG. 5 is a side elevation view of the adjustable connector shownpartially in section.

FIG. 6 is a perspective view of a face block of the block subassemblyshown in FIG. 2.

FIG. 7 is a perspective view of the tail block of the block subassemblyshown in FIG.2.

FIG. 8 is a top plan view of another embodiment of an adjustableconnector.

FIG. 9 is a top plan view of the adjustable connector of FIG. 8 shown ina disassembled state.

FIG. 10 a side elevation view of the adjustable connector of FIG. 8shown partially in section.

FIG. 11 is side view of the lowermost course of a retaining wall,according to another embodiment.

FIG. 12 is a perspective view of an embodiment of a block subassemblyutilizing pivotable dovetail connector elements shown in a disassembledstate.

FIG. 13 is a top plan view of the block subassembly shown in FIG. 12.

FIG. 14 is a top plan view of another embodiment of a block subassembly.

FIG. 15 is a cross-sectional view of the block subassembly of FIG. 14taken along line 15-15 of FIG. 14.

DETAILED DESCRIPTION

As used herein, the singular forms “a,” “an,” and “the” refer to one ormore than one, unless the context clearly dictates otherwise.

As used herein, the term “includes” means “comprises.”As used herein, agroup of individual members stated in the alternative includesembodiments relating to a single member of the group or combinations ofmultiple members. For example, the term “a, b, or c,” includesembodiments relating to “a,” “b,” “c,” “a and b,” “a and c,” “b and c,”and “a, b, and c.”

FIG. 1 shows a retaining wall 8 for retaining a sloped bank 6 againstsliding and slumping. The wall 8 is formed of several vertically stackedcourses or layers 4 a-4 d. Each layer 4 a-4 d is generally horizontaland extends in a rearward direction A into the bank 6.

Each layer in the illustrated embodiment is formed of a row ofside-by-side I-shaped subassemblies 10. Each subassembly typicallyincludes at least two vertically oriented planar blocks and anadjustable connector extending between or connected to the blocks. Asshown in FIG. 2, a veneer or face block 24 can have a textured facesurface 26 facing a forward direction B opposite the rearward directionA. The adjustable connector in particular embodiments comprises a nestedtube subassembly 68, which is attached to the rear of the face block 24,desirably at a vertical medial junction thereon. The nested tubesubassembly desirably extends perpendicularly from the face block 24 inthe rearward direction A. A tail block 18 can be attached to therearward end of the nested tube subassembly 68 so that it is parallel tothe face block 24, with the nested tube subassembly being attached tothe tail block desirably at a vertical medial junction. In someexemplary embodiments, the adjustable connector 68 can extend rearwardlyfrom the face block 24 at an angle that is less than 90 degrees (FIG.13).

For additional anchoring stability, particularly in the lower layer 4 aof walls having several layers, the I-shaped subassemblies 10 can beelongated in the rearward direction A by attaching one or more extensionsubassemblies 40. The lowest layer desirably extends into the slope adistance approximately equal to one-third of the final wall height. Theextension subassembly 40 includes a tail block 18 attachedperpendicularly to a nested tube subassembly 68 in a T-shapedarrangement. In each extension subassembly 40, the nested tubesubassembly 68 desirably attaches to and extends perpendicularly fromthe center of the tail block 18 of the standard I-shaped subassembly 10.

In the retaining wall 8 shown in FIG. 1, the I-shaped subassemblies 10are placed side-by-side so that their nested tube subassemblies 68 aregenerally parallel and the face blocks 24 are positioned end-to-end in acontinuous line. Thus, a pair of adjacent I-shaped subassemblies definesa generally rectangular chamber 38 suitable for filling with backfillmaterial 46 to provide stability and drainage. Each chamber 38 isdefined at its sides by the nested tube subassemblies of the respectiveI-shaped subassemblies and at its front and rear by the face blocks 24and tail blocks 18 of the respective I-shaped subassemblies. In certainembodiments, as described in greater detail below, utilizing adjustableconnectors which are pivotally connected to the face and tail blocks(FIG. 12), a pair of adjacent subassemblies may form a non-rectangularchamber.

As further shown in FIG. 1, the successive layers 4 a-4 d can bestaggered and can be set back by a small distance to create a slightlysloping wall face. Nonetheless, each face block 24 rests on the faceblocks of the layer below and each tail block 18 rests on the tailblocks of the layer below, with each nested tube subassembly 68 beingsuspended above the chamber 38 below. The face blocks 24 can be widerthan the tail blocks 18 so that convex curved walls may be formed bybringing together adjacent tail blocks 18 closer than a parallel spacingwould ordinarily dictate. To form a concave wall, the tail blocks can bespaced apart wider than ordinarily dictated but not so far apart thateach tail block 18 does not rest on the ends of the spaced apart tailblocks of the layer below. If a more sharply concave wall is desired,separate tail blocks may be added to support any unsupported members.

As shown in FIG. 2, the face block 24, nested tube subassembly 68, andtail block 18 can be assembled to provide an interconnected I-shapedsubassembly 10. In the interconnected state, the components of thesubassembly may not be disconnected or separated in any lateraldirection without breakage. The components of the subassembly in theillustrated embodiment are not merely held in place by frictional forcesand the presence of adjacent unconnected blocks. Each componentdesirably is securely mechanically engaged to at least one otheradjacent component.

The subassembly components in certain embodiments can be interconnectedby dovetail joints so that they may be separated only by verticallysliding one block with respect to the attached block. A dovetail jointmay be formed in any of a wide variety of geometries as long as theblocks are connected against lateral separation. Dovetail jointsgenerally have a male key or tongue 50 that mates with a female slot orgroove 52. Typically, the tongue is wider at some position toward itsfree end than at another position closer to its root. The female groove52 desirably is configured to closely conform to the male shape. In theillustrated embodiment, the face block 24 and tail block 18 define thevertical grooves 52, which are generally trapezoidal, with the facebeing wider than the aperture at the surface of each block. Compatiblemale tongues 50 are provided on the ends of the nested tube subassembly68, with the free end being wider than the root.

In alternative embodiments, the subassembly can be held in place byfrictional forces and/or the presence of adjacent unconnected blocks. Insuch embodiments, flat plates can be attached to the opposite ends ofthe adjustable connector 68 rather than male tongues 50, which platesare sized and shaped to be inserted into compatible slots or openings inthe blocks 18, 24.

FIG. 3 shows the assembled nested tube subassembly 68 with a male tongue50 at each end thereof. Each tongue 50 can have a sloped lower endsurface (not shown) corresponding to a sloped end surface 56 of thefemale groove 52 (FIG. 6).

FIG. 4 shows the component parts of the nested tube subassembly 68 in adisassembled state. The subassembly in the illustrated form comprises aninner tube 70 that is inserted into and therefore nests within an outertube 72. The tubes 70, 72 are configured to be telescopically slidablerelative to each other to adjust the overall length of the subassembly68. The nested tubes can be connected by a pin 76 (FIG. 5) that isinserted through alignment holes 74 formed in the inner and outer tubes70, 72. The alignment holes 74 allow the nested tube subassembly 68 tobe adjusted and maintained at a desired length by connection of thenested tubes through insertion of a connecting pin 76 into selectedalignment holes 74 in the tubes. FIG. 5 further shows the assemblednested tube subassembly 68 in cross section to illustrate the passage ofthe connecting pin 76 through the alignment holes 74 of the outer andinner trunk tubes. In the illustrated embodiment, alignment holes 74 areformed on diametrically opposing sides of each of the inner and outertubes to allow the pin 76 to extend completely through both tubes. Inalternative embodiments, the tubes 70, 72 can have alignment holes 74formed only along one side of each tube such that the pin 76 can extendinto but not completely through the tubes.

In particular embodiments, the length of the connector 68 can beadjusted between 24 inches and 44 inches, which would be desirable forconstructing walls having a height of 10 feet or less. For taller walls,the connector 68 can be adapted to have a greater maximum length.

While in the illustrated embodiment the inner and outer tubes 70, 72 arecylindrical, the tubes can have other cross-sectional shapes. Forexample, the tubes 70, 72 can have a cross-sectional profile that issquare, rectangular, triangular, or various combinations thereof, toname a few.

The inner and outer tubes 70, 72 can be made from various materials. Forinstance, the tubes 70, 72 can be formed from plastic or metal pipe andcan have a plate welded or otherwise attached to an end of each pipe forconnecting to a block.

The nested tube subassembly 68 can be used to adjust the overall lengthof the I-shaped subassemblies 10. In particular examples, such anadjustable I-shaped subassembly can enable a retaining wall 8 that canconform to particular contours of the sloped bank 6. In other particularexamples, such an adjustable I-shaped subassembly 10 can reduce thenumber of required extension subassemblies 40 (FIG. 1) and thus reducethe materials needed for constructing retaining wall 8.

FIG. 6 shows the face block 24 with the groove 52 only partiallybisecting the block. The groove in the illustrated embodiment does notentirely pass through the block, but terminates at an end surface 56that can be sloped in a direction facing generally upward and rearwardlyof the block. Thus, the lower portion of the block desirably is solidand unbroken by the groove, thereby increasing the strength of the blockand decreasing the risk of breakage at the groove 52.

The face block 24 can further include alignment channels 58 definingoblong bores 62 passing vertically through the entire block. Eachalignment channel 58 can include a rear pocket 60 in communication withthe alignment channel 58 and extending to a limited depth. An alignmentplug 30 (FIG. 1) comprising a rectangular lower portion 32 and a pinshaped upper portion 34 can be used to interconnect vertically adjacentblocks. The lower portion 32 can be inserted into the alignment channel58 of a block such that the upper portion 34 extends upwardly and intoan alignment channel 58 in an overlying block. The pin 34 desirably isoffset toward one end of the lower portion 32 of the plug to permitconstruction of vertical courses (i.e., no setback) or courses that areset back relative to each other. If zero setback is desired (the faceblocks are vertically aligned), the alignment plug 30 is placed in analignment channel in a forward position such that the pin 34 extendsupwardly from a location closer to the front portion 62 of the alignmentchannel 58. To create a setback between two courses, the alignment plug30 is placed in an alignment channel in a reversed position such thatthe pin 34 extends upwardly from a location closer to the rear pocket 60of the alignment channel 58. The alignment holes desirably are generallycentered on points ¼ and ¾ of the distance along the length of the faceblock 24. In alternative embodiments, the alignment channels 58 can beused to retain vertical reinforcing bars passing vertically throughseveral layers of the wall. In addition, the alignment channels 58 aredesirably elongated to provide lateral accommodation for block offset incurved walls with setback.

FIG. 7 shows the tail block 18 which can have a male tongue 50 formed oneach end to provide optional lateral attachment to the blocks, and witha female groove 52 centrally defined on each face according to theconfiguration of the face block 24. The grooves 52 can be orientedback-to-back and spaced apart by a solid web 66 of block material toprovide adequate strength.

The tongues 50 and grooves 52 can be similarly tapered along theirvertical lengths so that each dovetail joint is secured against excessmotion and slippage by the tongue 50 being wedged into the groove.

FIGS. 8 and 9 show a second embodiment of the adjustable connector. Thisembodiment comprises a subassembly 78 comprising an inner tube 80 thatis slidably insertable into an outer tube 82 in a telescoping manner.The overall length of subassembly 78 can be adjustable. In thisembodiment, a locking pin 84, extending radially outward from the outersurface of the inner tube 80 can be provided. An elongated,longitudinally extending alignment channel 86 can be formed on one sideof the outer tube 82 to accommodate the locking pin 84 and allow forinsertion of the inner tube into the outer tube. The inner and outertubes can be positioned into a locked configuration by rotating eithertube to insert the locking pin 84 into one of several locking channels88 extending perpendicularly from the alignment channel 86. A maletongue 50 can be provided on the distal end of each tube 80, 82 forinsertion into corresponding grooves in blocks 18, 24. The male tongues50 desirably are positioned such that rotating the tubes into the lockedconfiguration to position the pin 84 into a selected channel 88correctly orients the male tongue for insertion into a female groove 52as described herein. FIG. 10 shows the locked configuration of thenested tube subassembly 78 in cross section.

In alternative embodiments, the locking pin 84 can extend radiallyinward from the inner surface of the outer tube 82. The alignmentchannel 86 and the locking channels 88 can be formed on the outersurface of the inner tube 80. The inner and outer tubes can bepositioned into a locked configuration by rotating either tube to insertthe locking pin 84 into one of several locking channels 88 extendingperpendicularly from the alignment channel 86.

Another embodiment is shown in FIGS. 14 and 15. In this embodiment, theadjustable connector 68 can be provided with radially extending pins 110at each end and the rear face of the face block 24 and the front face ofthe tail block 18 can be formed with respective openings 114, 116.Opening 114 is sized to receive the forward end portion of the connector68 and a corresponding pin 110, while opening 116 is sized to receivethe rear end portion of the connector 68 and a corresponding pin 110.Opening 114 is in communication with a laterally extending slot 112 thatis sized to receive a corresponding pin 110. Similarly, opening 116 isin communication with a laterally extending slot 118 that is sized toreceive a corresponding pin 110. To assemble the connector and theblocks, as best shown in FIG. 15, the end portions of the connector 68are first inserted into openings 114, 116 with the pins 110 in avertically upright position, and then the connector is rotated to rotatethe pins 110 into the slots 112, 118, thereby “locking” the connector 68to the face and tail blocks 24, 18.

In other alternative embodiments, the adjustable connector can compriseany construction configured to interconnect a face and tail block and toadjust the spacing therebetween. For example, the adjustable connectorcan comprise a first elongated connection member and a second elongatedconnection member. A first end portion of the first connection member isadapted to be connected to the face block and a second end portion ofthe second connection member is adapted to be connected to the tailblock. The first and second connection members have second end portionsthat are adapted to be connected to each other at various locations tovary the spacing between the face and tail blocks. For example, thesecond end portions of each connection member can be formed with aplurality of longitudinally spaced openings adapted to receive a pin orbolt to connect the second end portions to each other at selectedlocations. The connection members can comprise flat, plate-like members,tubular members, I-shaped members, C-shaped members, or various othershapes.

In another embodiment, a spring-loaded locking pin similar to pin 84 ofFIG. 9 can be provided on the outer wall of an inner tube 70. Thespring-loaded pin extends radially outwardly from the inner tube and canbe sized to extend through a plurality of alignment holes 74 (FIG.3)formed in an outer tube. In other alternative embodiments, the lockingpin can be provided on the outer tube of the adjustable connector andthe alignment channel or alignment holes can be formed in the innertube.

In addition, the face and tail blocks 24, 18 can be constructed invarious shapes and sizes. For example, the face and tail blocks can besquare, rectangular, trapezoidal, diamond-shaped, or variouscombinations thereof.

In another embodiment, a block subassembly 10 can comprise a face block24, a tail block 18, and a connector of fixed-length extending betweenand connecting the face block to the tail block. The connector can beformed from materials that are less expensive than concrete, and in someembodiments, can be fabricated to have a selected length to suit theneeds of a particular application. In one example, the connector cancomprise a piece of rebar or pipe having plates welded at its ends. Theplates are sized to be inserted into the openings 52 in the blocks 24,18. The openings 52 can be appropriately sized and shaped to complementand readily accept the shape of the plates of the connector.

Block assemblies having such a fixed-length connector can be used for aselected number of courses at the base of the wall where the depth ofthe wall is greatest and adjustable connectors can be used for coursesabove the base where the depth of the wall can be reduced.

FIG. 11 shows an embodiment of the lowermost course of a retaining wallformed from block subassemblies 10. In this embodiment, the connector 68of each subassembly in the lowermost course can be provided with adownwardly projecting anchor, or projection, 100. The anchor 100 can beconnected to the outer tube 72 by any suitable technique or mechanism(e.g., by welding or mechanical fasteners). The anchor 100 can be, forexample, a piece of rebar or a tubular member (e.g., metal or plasticpipe). The anchor 100 extends downwardly into a trench 102 formedunderneath the lowermost course of blocks between the face block 24 andthe tail block 18.

After the lowermost course of side-by-side block assemblies 10 is formedover the trench 102, the trench can be filled with concrete to form aconcrete footing 104 that extends upwardly into the voids betweenadjacent block subassemblies 10. The anchor 100 helps anchor each blocksubassembly to the concrete footing 104. The concrete footing 104 iseffective to increase the sliding resistance of the wall. This allowsthe wall to be constructed with a smaller base width than would normallybe required, which minimizes excavation and provides more space in theembankment behind the wall, such as for placement of utility easementsor other structures. Additional details about forming a retaining wallwith the footing 104 can be found in co-pending U.S. application Ser.No. 10/591,736, which is the national stage of PCT Application No.PCT/US2005/008744 (published as WO2005/100700), which is incorporatedherein by reference. The block assemblies 10 used to form the remainingcourses of the wall need not be provided with anchors 100 connected tothe connectors 68.

In other alternative embodiments, the anchor 100 can be connected to theinner tube 70. Similarly, in other alternative embodiments, theconnector 68 of each subassembly in the lowermost course could be afixed-length connector having an anchor 100.

FIG. 12 shows a perspective view of an embodiment of a block subassemblyutilizing pivotable connector elements that allow adjustment of theangle between the connector 68 and one or both of the face and tailblocks. In this embodiment, the adjustable connector 68 comprises apivotable connector 90 coupled to each of the inner and outer tubes 70,72. Each pivotable connector 90 can comprise a male dovetail connectorelement 92 and upper and lower ears 94 extending from the connectorelement 92. The ears 94 have vertical holes 96 sized to receive a pivotpin 64 and are vertically spaced to receive a respective end portion 98of a tube 70, 72. Each end portion 98 also has vertical hole 106 sizedto receive a corresponding pivot pin 64. The vertical holes 96 and 106can be aligned and the pivot pin 64 inserted through the holes topivotably connect the adjustable connector 68 to the pivotable connector90. As further shown in the exemplary embodiment in FIG. 12, theadjustable connector 68 can be attached to the face block 24 and thetail block 18 by sliding the connector elements 92 vertically into thegrooves 52 in the face and tail blocks.

As best shown in FIG. 13, the connector 68 can be pivoted in ahorizontal plane relative to the face block 24 and/or the tail block 18(as indicated by double-headed arrow in order to vary the angle θbetween the connector 68 and the rear face 28 of the face block 24and/or the angle α between the connector 68 and the front face 38 of thetail block 18. In addition, the face block 24 and/or the tail block 18can be pivoted relative to the connector 68 so that the rear face 28 ofthe face block is not parallel to the front face 38 of the tail block.Advantageously, the adjustability of connector 68 relative to the faceand tail block provides greater flexibility when constructing retainingwalls. For example, when forming concave walls, a tail block can bepivoted relative to the respective face block of the same subassembly toposition the tail block closer to a tail block of an adjacentsubassembly in order to support a tail block of the course above. Inaddition, the use of a connector 68 that is pivotable at least withrespect to the face block 24 enables construction of a convex retainingwall having a smaller radius of curvature than would normally bepossible.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. It should beapparent to those skilled in the art that the illustrated embodimentsmay be modified without departing from the principles described. Rather,the scope of the invention is defined by the following claims. Itherefore claim as my invention all that comes within the scope andspirit of these claims.

1. A subassembly for constructing a retaining wall comprising: a firstblock; a second block spaced from the first block, the first and secondblock defining a space therebetween for receiving backfill material whenconstructing the wall; and an adjustable connector extending between andconnected to the first and second blocks, the adjustable connectorconfigured to have an adjustable length to adjust the spacing betweenthe first and second blocks.
 2. The subassembly of claim 1, wherein theadjustable connector comprises an inner tube and an outer tube, theinner tube being telescopically slidable into and out of the outer tubeto adjust the length of the adjustable connector.
 3. The subassembly ofclaim 2, wherein one of the inner and outer tubes has at least onealignment hole and the other of the inner and outer tubes has aplurality of alignment holes, and the subassembly further comprises apin that can be inserted into the at least one alignment hole and aselected one of the plurality of alignment holes to restrictlongitudinal movement of the tubes relative to each other.
 4. Thesubassembly of claim 2, wherein the inner tube has an outer surfacehaving a locking pin extending radially outward from the outer surface,and the outer tube comprises an elongated longitudinally extendingalignment channel on one side and a plurality of longitudinally spacedlocking channels extending perpendicularly from and connected to thealignment channel, the alignment channel being configured to accommodatethe locking pin and allow insertion of the inner tube into the outertube, such that the inner and outer tubes can be positioned into alocked configuration by rotating either tube to insert the locking pininto a selected one of the plurality of locking channels.
 5. Thesubassembly of claim 2, wherein the outer tube has an inner surfacehaving a locking pin extending radially inward from the inner surface,and the inner tube comprises an elongated longitudinally extendingalignment channel on one side and a plurality of longitudinally spacedlocking channels extending perpendicularly from and connected to thealignment channel, the alignment channel being configured to accommodatethe locking pin and allow insertion of the inner tube into the outertube, such that the inner and outer tubes can be positioned into alocked configuration by rotating either tube to insert the locking pininto a selected one of the plurality of locking channels.
 6. Thesubassembly of claim 1, wherein the adjustable connector comprises afirst elongated connection member and a second elongated connectionmember, and the first and second elongated connection members areadapted to be connected to each other at a plurality of locations tovary the spacing between the first and second blocks.
 7. The subassemblyof claim 6, wherein one of the first and second connection members hasat least one alignment hole and the other of the first and secondconnection members has a plurality of alignment holes, and thesubassembly further comprises a pin that can be inserted into the atleast one alignment hole and a selected one of the plurality ofalignment holes to restrict longitudinal movement of the connectionmembers relative to each other.
 8. The subassembly of claim 1, whereinthe adjustable connector is configured to be pivotably connected to atleast one of the first and second blocks, such that the adjustableconnector can be pivoted, in a horizontal plane, to vary the anglebetween the connector and the block to which it is pivotably connected.9. The subassembly of claim 1, wherein the first block comprises a rearface, the second block comprises a front face and a rear face and theadjustable connector comprises a first end portion and a second endportion, and wherein the first end portion of the adjustable connectorcan be connected to the rear face of the first block and the second endportion of the adjustable connector can be connected to the front faceof the second block.
 10. The subassembly of claim 9, wherein each of thefirst and second end portions of the adjustable connector comprises adovetail element for interlocking with complementary dovetail elementson the first and second blocks.
 11. The subassembly of claim 9, whereineach of the first and second end portions of the adjustable connectorcomprises a male connecting element, the rear face of the first blockcomprises an opening sized to receive the male connecting element of thefirst end portion of the adjustable connector, and the front face of thesecond block comprises an opening sized to receive the male connectingelement of the second end portion of the adjustable connector.
 12. Thesubassembly of claim 9, wherein each of the first and second endportions of the adjustable connector comprises a radially extending pin,the rear face of the first block comprises a slot complementarily sizedto interlock with the radially extending pin of the first end portion ofthe adjustable connector, and the front face of the second blockcomprises a slot complementarily sized to interlock with the radiallyextending pin of the second end portion of the adjustable connector. 13.The subassembly of claim 9, wherein each of the first and second endportions of the adjustable connector comprises a pivotable dovetailconnector element, and the rear face of the first block and the frontface of the second block comprise complementary dovetail connectorelements, for interlocking with the pivotable dovetail connectorelements on the adjustable connector, the pivotable dovetail connectorelements allowing the first and second blocks to be pivoted relative tothe adjustable connector.
 14. The subassembly of claim 13, wherein thepivotable dovetail connector element of each of the first and second endportions of the adjustable connector comprises a male dovetail connectorelement and a pivot pin pivotably connecting the dovetail connectorelement to the adjustable connector.
 15. A building block system forbuilding a retaining wall comprising: a plurality of face blocks eachhaving a rear face; a plurality of adjustable connectors each having afirst end portion and a second end portion, each adjustable connectorbeing configured to have an adjustable length between its first andsecond end portions; and a plurality of tail blocks each having a frontface and a rear face, wherein the blocks and adjustable connectors maybe assembled to form block assemblies each having an adjustableconnector connected at its first end portion to the rear face of a faceblock, the adjustable connector extending rearwardly from the rear faceof the face block, with the second end portion of the adjustableconnector connected to the front face of a tail block.
 16. The system ofclaim 15, wherein additional adjustable connectors and tail blocks canbe attached to extend rearwardly from the rear face of a tail block toform elongated block assemblies of variable selectable lengths.
 17. Aretaining wall comprising: at least first and second vertically-stackedcourses comprising a plurality of block subassemblies placedside-by-side in each course, wherein each block subassembly comprises aface block having a front surface exposed in a face of the wall, a tailblock positioned behind and spaced from the face block, and anadjustable connector extending between and connected to the face andtail blocks, the adjustable connector configured to have an adjustablelength to adjust the spacing between the face and tail blocks.
 18. Theretaining wall of claim 17, wherein the plurality of block subassembliesare placed side-by-side such that a pair of adjacent block assembliesdefine a chamber therebetween, and the chamber contains backfillmaterial.
 19. The retaining wall of claim 17, wherein the first coursecomprises the lowermost course of the wall and a trench extendsunderneath the first course, wherein one or more of the adjustableconnectors in the first course comprise anchors projecting downwardlyinto the trench and being anchored to a concrete footing in the trench.20. The retaining wall of claim 17, wherein the length of the adjustableconnectors in the second course is smaller than the length of theadjustable connectors in the first course.
 21. A method of constructinga retaining wall, comprising forming at least first and secondvertically-stacked courses comprising a plurality of block assemblies,at least some of the block assemblies in at least one course eachcomprising a face block, a tail block, and an adjustable connector thatis adjustable in length to adjust the spacing between the face and tailblocks.
 22. The method of claim 21, wherein the act of forming the firstand second courses comprises: adjusting the length of an adjustableconnector; connecting a first end of the adjustable connector to arespective face block; and connecting a second end of the adjustableconnector to a respective tail block.
 23. The method of claim 21,wherein the act of forming the first and second courses comprises:placing the block assemblies side-by-side in each course, such that eachpair of adjacent block assemblies defines a chamber therebetween; andfilling the chamber with backfill material.
 24. The method of claim 21,wherein the first course comprises the lowermost course of the wall, atrench extends underneath the first course, and building the firstcourse comprises: positioning the block assemblies, each having anadjustable connector comprising an anchor, such that the anchors projectdownwardly into the trench; and filling the trench with concrete to fixthe anchors to the concrete.
 25. A subassembly for constructing aretaining wall comprising: a first block; a second block spaced from thefirst block; and a connector comprising an elongated body having firstand second opposite end portions, the first end portion being connectedto the first block and the second end portion being connected to thesecond block, the connector being pivotable relative to at least thefirst block to permit adjustment of the angle between the connector andthe first block.
 26. The subassembly of claim 25, wherein the connectoris configured to have an adjustable length to adjust the spacing betweenthe first and second blocks.
 27. The subassembly of claim 25, whereinthe first end portion of the connector is pivotable relative to thefirst block at a pivot pin.
 28. The subassembly of claim 25, wherein theconnector is pivotably connected to the first and second blocks.
 29. Thesubassembly of claim 25, wherein the first block has an opening and thefirst end portion of the connector comprises a male connector elementadapted to be received in the opening of the first block, the maleconnector element being pivotably connected to the remaining portion ofthe connector.